Page 29 - Industrial Technology October/ November 2020 issue

DESIGN ENGINEERING

Material considerations

SRPINGS & DAMPERS

THERE ARE A NUMBER OF FACTORS TO TAKE INTO ACCOUNT
IN A SPRING’S APPLICATION BEFORE GOING AHEAD WITH
THE DESIGN AND MANUFACTURING PROCESS, AS AIREDALE
SPRINGS CHAIRMAN, TIM PARKINSON, EXPLAINS

spring’s environment will hugely impact the Specific temperatures: When choos-
materials chosen. It's crucial to consider the ing materials, it’s also important to
application environment because this will impact consider whether the spring will need to
Athe final product – for example, if you need a operate in an environment with low or
spring for an electronic product, then that spring will high temperatures. If springs are used in
probably need to be conductive and/or possess resistance environments with temperatures outside
to heat. of their recommended levels, they can
Load conditions: The load conditions represent a key become damaged, deformed or brittle.
consideration: can the spring withstand the stress Chrome silicon alloys, for example, are
conditions that it will be put under? The pressure or a good option for sectors and applications
tension placed on a spring will impact its performance and where heat is a concern, since they can
lifespan, so it’s critical that the spring is made from a withstand high temperatures; in fact, their
durable material capable of meeting these application working temperatures are usually over 200°C. These need to take hygiene into consideration. Not only do
loads. There are two different types of loads: alloys are also suitable for high-stress applications, since springs used in these sectors have to be durable and
l With a static load, which refers to a fixed load that is they have a high degree of fatigue resistance, like fuel capable of handling high-pressure environments, but they
applied in a gradual manner, the spring only needs to injector springs. Low temperatures also require careful also have to be easy to clean and disinfect, especially in
operate for a low number of cycles; its ability to withstand material consideration. Industries that work with low today’s climate.
stress in these conditions will depend on the tensile temperatures include the energy, agriculture and health Stainless steels are suitable for these applications, as
strength of the material. sectors, and non-ferrous alloys, such as those containing they help to keep places clean, reduce the risk of infection
l A dynamic load consists of a force that is applied nickel or the 300 series stainless steels, can perform well and help to save lives.
varyingly, and it means the spring itself is moving due to in both high and low temperatures. Magnetic properties: Certain environments require the
the pressure applied. Nearly all aluminium alloys can also be applied at use of magnetic or non-magnetic materials, so this is
Materials like hard-drawn steel wire, which are more temperatures around –45°C while still functioning well, another property to consider. High carbon steel is a good
cost-effective, are suitable for applications where the load and high-alloy austenitic stainless steels can work at example of a material that is widely popular, cost-effective
applied on the spring is static. Certain families of stainless temperature below –196°C. and highly magnetic – however, the alloy has a low degree
steels, like the Duplex one, have high tensile strength, Resistance to corrosion: Corrosive environments, like of resistance to corrosion and should be used in a sealed
which means they can withstand a higher degree of those found in chemical plants or in oil platforms at sea, environment.
pressure. They are also found in sectors like transportation require the use of materials that can not only withstand If the environment application requires a non-magnetic
(rail, cycling, etc). If the spring will be under a dynamic repeated use but that can also resist corrosion over time. spring because of the surrounding materials (so nothing
load, it also needs to have good resistance to fatigue – While no spring – or any other part – will last forever, you oscillate, for instance), then something like aluminium,
music wire is a good option for that. have a better chance of maximising its longevity and of titanium and bronze, just to name a few, are your best bet.
ensuring a good performance by Weight restrictions: Industries like aerospace need
selecting the right materials. springs and components that are strong, durable and long-
Corrosion happens when metal lasting, as well as low in weight. In aircraft, every gram
reacts to its surroundings, but some are count, so materials like aluminium are often the preferred
less susceptible than others. Ideally, you option.
3
should look for metals and alloys like: This is because aluminium weighs only 2.7g/cm ,
l Cold-drawn copper alloys, which are which is around a third of that of steel and allows for
excellent where good electrical vehicles and aircraft to reduce dead-weight and improve
conductivity is required and are also energy consumption. A plane with many steel parts would
highly resistant to corrosion. never fly as well or operate as efficiently as one with
l Nickel alloys and chromium alloys, aluminium components.
as they’re often resistant to corrosion in There are many material implications when it comes to
addition to being resistant to wear and different application environments, so choosing a spring
tear and oxidation, making them manufacturer who understands this is vital. Airedale
suitable for a wide range of applications. Springs has 75 years of knowledge and expertise, so we’re
Hygienic and clinical environments: able to deliver high-quality springs and wire forms to
While this may not apply to everything, clients in a large number of industries.
industries like the food and medical ones MORE INFORMATION: www.airedalesprings.co.uk

October/November 2020 • INDUSTRIAL TECHNOLOGY 29